1. Field of the Invention
This invention relates to devices for ground handling aircraft, specifically those equipped with skid-type landing gear such as helicopters.
2. Description of Prior Art
Previously the typical means of maneuvering a helicopter with skid-type landing gear was (1) to attach its factory-supplied ground handling wheels and utilize two or more personnel to balance, maneuver and push the aircraft or (2) to utilize a hydraulic lifting and towing device such as that shown in U.S. Pat. No. 4,223,856 to DiVincenzo, or No. 4,033,422 to Benning.
Such devices have numerous disadvantages in maneuvering and lifting the aircraft, such as:
(1) Utilizing solely the ground wheels requires two or more personnel to balance the aircraft on the wheels while pushing and maneuvering the aircraft; PA1 (2) Hydraulic devices are complex and require sophisticated maintenance. Such devices have also been known to damage the aircraft by improper use or placement of the powerful hydraulic components. The integral hydraulic devices can only be utilized with a single aircraft. In addition, once the aircraft is moved to its new location, it is placed on the ground again, and if it is to be moved again the hydraulic device must be used again.
The difficulty with DiVincenzo No. 4,223,856 is that the weight of the helicopter is borne by a yoke which is attached in the center to a carriage and at ends to the aircraft. As a result, the aircraft is essentially hinged at the yoke connection to the carriage creating an unstable balance situation. In addition, the skids require special attachments.
The difficulty with Benning No. 4,033,422 is that the helicopter is also in an unstable balance situation due to the lifting apparatus. The instant invention overcomes these dificiencies by providing a wide wheel base with the helicopter weight on the skids.
A further drawback is the various couplings and connections involved in attaching the helicopter. Also, many devices are self-propelled and a power failure renders the device useless. In addition, the more complex the hydraulic or self-propelled device the greater the cost of purchase and maintenance. A need has been long felt in the aviation field for a ground handling apparatus which can easily attach to the skid-type landing gear of aircraft such as helicopters to provide a mobility capability which is generally non-existent in aircraft with skids and which can remain attached to the aircraft for subsequent moves. If each aircraft has its own dolly, an entire fleet of aircraft could be rapidly moved if conditions so required. The device must be capable of remaining attached to the aircraft for on-demand, immediate movement and therefore must be inexpensive but reliable. The apparatus must be able to be operated by a minimum of personnel and consist of simple components to reduce maintenance and increase availability. The apparatus must be sturdy and rugged to handle the weight of the aircraft. Previous ground handling assemblies were not capable of providing all of the above requirements. The instant invention satisfies the above requirements.